At their most basic, a valve controls the flow of a fluid or gas. Valves are integral components in almost every gas or fluid system. There are many types of valves in use today. In the case of check valves, there are ball, dual plate or double-door, spring assisted, piston or lift, and swing checks. While no one type of valve is good for all applications, each has its advantages.
The pressure relief valve is a type of valve used to control or limit the pressure in a system. The pressure is relieved by allowing the pressurized fluid to flow through the valve out of the system. The relief valve is designed to open at a predetermined pressure to protect pressure vessels and other equipment from being subjected to pressures that exceed their design limits. When the set pressure is exceeded, the relief valve becomes the “path of least resistance” as the valve is forced open and the fluid or gas is allowed to escape. As the fluid or gas escapes, the pressure inside the vessel will decrease. Once it reaches the valve's reseating pressure, the valve will close.
However, in most systems that use moving parts, there are problems specific to the part. Common valve problems include noise, vibration, reverse flow, sticking, leakage, component wear, or damage. One of the most common problems with valves are reverse flow. Reverse flow can be costly, depending upon the system in which the valve is employed.
In addition, valves are subject to wear—whenever one part rubs against another part, wear is a result, which leads to leakage and eventual failure of one or more components. A component failure can result in the valve not performing its function, which in the case of a check valve is primarily to prevent reverse flow and in the case of a pressure relief valve, preventing vessel overpressure.
Therefore, there remains a need to overcome one or more of the limitations in the above-described, existing art. The discussion of the background to the invention included herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the claims.
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown. The Figures are provided for the purpose of illustrating one or more embodiments of the invention with the explicit understanding that they will not be used to limit the scope or the meaning of the claims.